Drive device for a fan module

ABSTRACT

A drive device for a fan module comprises an electric motor, a housing and a vibration damper for fastening the electric motor to the housing in a manner which damps vibrations. The electric motor has a radial engagement element for engaging into the vibration damper, and the housing has a radial recess for receiving the vibration damper. Here, the vibration damper frames the engagement element in the radial direction thereof.

BACKGROUND OF THE INVENTION

The invention relates to a drive device for a fan module and a method for producing such a drive device.

A fan module, as, for example, is used on board a motor vehicle for conveying fresh air into a passenger compartment, typically comprises an electric motor with a fan wheel. The electric motor is accommodated in the housing in a manner which damps vibrations, and the housing is prepared for installation in an air duct of the motor vehicle. By means of accommodating the electric motor in a manner which damps vibrations, vibrations and impacts of the motor vehicle are on the one hand kept away from the electric motor; thus enabling said motor to have a longer service life. On the other hand, vibrations of the electric motor are decoupled from the motor vehicle in order to prevent them from leading to an acoustically perceptible sound at another location, which sound can be perceived as being unpleasant by a vehicle occupant in the passenger compartment of the motor vehicle.

An elastic element is normally disposed between the electric motor and the housing in order to decouple the vibrations of the electric motor from the vehicle. To this end, the housing comprises a recess for receiving the elastic element, whereas the electric motor has a device for engaging into the elastic element. A dumbbell-shaped design of the elastic element in the form of two spherical sections connected to one another by a crosspiece is typical, the device engaging into the elastic element in the region of the crosspiece.

If the fan module is operated at high temperatures, a spring stiffness of the elastic element significantly decreases. As a result, the radially protruding engagement element of the electric motor can come into contact with a periphery of the recess along the circumferential direction of the electric motor, whereby all damping is circumvented. It is therefore the aim of the invention to specify a drive device for a fan module which offers an improved protection against such a penetration. A further aim of the invention consists of specifying a production method for such a fan module.

SUMMARY OF THE INVENTION

A drive device for a fan module comprises an electric motor, a housing and an elastic element for fastening the electric motor to the housing in a manner which damps vibrations. The electric motor has a radial engagement element for engaging into the elastic element, and the housing has a radial recess for receiving the elastic element. In so doing, the elastic element frames the engagement element on a radial section thereof.

Due to the special design of the elastic element, the possibility that the engagement element comes into contact with a periphery of the recess is practically eliminated even in the case of the elasticity or the damping capability of the elastic element being severely compromised due, for example, to ageing, wear or high temperature. Impacts can thereby be prevented and thus the service life of the electric motor can be extended and acoustic interferences in the region of the drive module can be prevented. As a result of the increased security with regard to a collision of the engagement element with the housing, the elastic element can be less robustly dimensioned; thus enabling a preloading to be minimized. In so doing, the damping properties of the elastic element can be improved in both the short term and the long term. Moreover, a structural load on the housing can be minimized. In addition, contact surfaces between the elastic element and the engagement element or, respectively, the recess can be enlarged; and therefore a material fatigue, in particular of the elastic element, can be made less likely.

The elastic element is preferably formed such that a spring stiffness of the elastic element along a rotational direction of the electric motor is smaller than parallel to the rotational axis of the electric motor. Vibrations of the electric motor along the rotational direction thereof can thereby be better decoupled from the housing while at the same time a support of said electric motor in the direction of the rotational axis thereof remains rigid. As a result, a collision of a fan wheel connected to said electric motor with an air guidance duct can be prevented.

With regard to the shape of the recess, the elastic element can comprise a radial cut-out in order to reduce a contact surface to the recess in the circumferential direction of the electric motor. In so doing, a heat dissipating surface area of the elastic element is enlarged; thus enabling heat from the elastic element to be better released. As a result of this measure, the service life of the elastic element can be increased, in particular at high operating temperatures. On account of the same measure, the spring stiffness of the elastic element can also be decreased in the circumferential direction of the electric motor.

The elastic element can also be formed in such a way that a radial outer side of the elastic element is curved in order to fit closely against a section of the housing. As a result, a rolling motion of the elastic element along a radial peripheral surface of the recess is minimized on the one hand, whereby wear to the elastic element is reduced and a stiffness constant of said elastic element can be evenly maintained. On the other hand, an improved dissipation of heat from said elastic element to the housing of the drive device can thereby be realized.

In one embodiment of the invention, the elastic element is formed in such a way that a periphery of the electric motor which is in the circumferential direction rests in a planar fashion against a corresponding periphery of the recess. As a result, the recess can be completely filled by the vibration damper along the circumferential direction of the electric motor; and therefore a preloading of the elastic element can be reduced or omitted. The stiffness constant of the elastic element in the circumferential direction of the electric motor can thereby for the most part be determined by the selection of the material or the Shore hardness of the elastic element.

In a preferred embodiment of the invention, the engagement element comprises a round metal web, which is fastened to a pole pot of the electric motor. As a result of said engagement element which is easy to produce, sharp edges can be avoided in the engagement region with the elastic element.

The metal web is preferably formed on one side by upsetting, the upset end being disposed between the pole pot and a flux-return ring of the electric motor. This can facilitate a simple and cost effective production.

The elastic element is preferably symmetrically shaped with respect to a rotation about a radius of the electric motor. An improper installation of the elastic element in an incorrect position can thereby be prevented. Additional features in the sense of a Poka Yoke strategy (“fail safe principle”) can be omitted where appropriate, which can lead to further cost reductions.

A cover which axially closes the housing is provided in one embodiment, the elastic element being held in the axial direction in a form-fitting manner between a periphery of the recess and the cover. In this way, the electric motor can be easily mounted in and dismounted from the housing.

A method according to the invention for producing a drive device comprising the described engagement element in the form of a metal web consists of the following steps: inserting the metal web through a corresponding recess in the pole pot, inserting the flux-return ring into the pole pot, connecting the flux-return ring to the pole pot, sliding the elastic element onto the metal web and inserting the electric motor into the housing so that the elastic element is accommodated in the recess of the housing.

In contrast to a drive device of the prior art comprising an engagement element, which is implemented as a lug of the pole pot of the electric motor that is bent radially outwards, the drive device previously described can be produced more simply in the manner specified above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described more precisely with reference to the attached drawings, in which:

FIG. 1 shows a schematic exploded view of a fan module;

FIG. 2 shows in detail a section of the electric motor from FIG. 1;

FIG. 3 shows a vibration damper;

FIG. 4 shows a vibration damper on the electric motor from FIG. 1;

FIG. 5 shows an engagement element of the electric motor from FIG. 1;

FIG. 6 shows a vibration damper for the engagement element from FIG. 5;

FIG. 7 shows an engagement element of the electric motor from FIG. 1;

FIG. 8 shows a vibration damper for the engagement element from FIG. 7; and

FIG. 9 shows a flow diagram of a method for producing the drive module from FIG. 1.

DETAILED DESCRIPTION

FIG. 1 show a schematic partial view of a fan module 100, in longitudinal section and in an exploded view. The fan module 100 comprises a fan wheel 105 and a drive device 110. The drive device 110 comprises an electric motor 115 which is accommodated in a housing 120 having a cover 125. An elastic element 130 is provided for mounting the electric motor 115 in relation to the housing 120 or the cover 125. The elastic element 130 is typically manufactured from a plastic or rubber material.

A recess 135 for receiving the elastic element 130 is provided on the housing 120, wherein along a rotational axis 140 of the electric motor 115, the recess 135 is closed at the top by the cover 125 and is open towards the inside in the radial direction. The elastic element 130 is formed in such a manner that it rests on five sides against peripheries of the recess 135, while the sixth side faces the electric motor 115 in the radial direction.

A plurality of elastic elements 130 having corresponding recesses 135 and engagement elements 145 is typically distributed around a circumference of the electric motor 115. Not all of the elastic elements 130 have to thereby be at the same height with respect to the rotational axis 140 of the electric motor 115. Furthermore, angles between the elastic elements 130 with respect to the rotational axis 140 of the electric motor 115 can vary.

In the radial direction, the elastic element 130 has a recess for receiving an engagement element 145 radially protruding from the electric motor 115. In a preferred embodiment of the invention, not only the radial engagement element 145 of the electric motor 115 is engaged with the recess of the elastic element 130, but a surface of the elastic element 130 facing the electric motor 115 is at the same time in engagement with a radial periphery of the electric motor. As a result, the electric motor 115 is mounted in an improved manner with respect to the housing 120 or the cover 125 so that forces and vibrations between said electric motor 115 and said housing 120 or said cover 125 are essentially transmitted only by the elastic element 130.

FIG. 2 shows in detail a section of the electric motor 115 from FIG. 1 in the region of the engagement element 145. The engagement element 145 is formed here by a substantially cylindrical or hollow cylindrical element, in particular a steel wire. The steel wire 145 passes through a recess in a pole pot 205 of the electric motor 115. The steel wire 145 is upset on the left end thereof so that the diameter of said steel wire 145 is larger than the diameter of the recess of the pole pot 205 and said steel wire 145 cannot slip to the right through said recess. A section of a flux-return ring 210 of the electric motor 115 is depicted to the left of the upset end of the steel wire 145. The flux-return ring 210 prevents the steel wire 145 from slipping to the left into the electric motor 115.

FIG. 3 shows an elastic element 300 corresponding to the elastic element 130 from FIG. 1. The elastic element 300 can particularly be used on the drive device 110 from FIG. 1 in conjunction with the engagement element 145 depicted in FIG. 2.

A coordinate system displays, in relation to the rotational axis 140 of the electric motor 115 in FIG. 1, a radial direction x, an axial direction y and a circumferential direction z.

The elastic element 300 has a round recess 305, which runs in the x-direction, for receiving the engagement element 145 from FIGS. 1 and 2. The elastic element 300 is rotationally symmetrical with respect to the recess 305, a rotation about an angle of 180 mapping the elastic element 300 onto itself.

An external surface of the elastic element 300 located in the x-direction is curved to match a corresponding contact surface of the recess 135 of FIG. 1. The curvature passes continuously into a curvature of the peripheries of the elastic element 300 located in the z-direction. Limitations of the elastic element 300 along the y-direction correspond again to peripheries of the recess 135 or of the cover 125.

The lateral surfaces of the elastic element 300 oriented in the z-direction are reduced in size in that four round cut-outs were introduced on the corners of the positive and negative y- and z-directions respectively along the x-direction. The resulting cut surfaces can contribute to enlarging a surface area of the elastic element 300 in order to facilitate a heat dissipation, which, for example, can result in the elastic element on account of the damping behavior of the same.

FIG. 4 shows an elastic element 400 on an electric motor 115 from FIG. 1. The information is displayed with the viewing direction substantially from the rotational axis 140 of the electric motor 115 radially outwards. A coordinate system corresponding to that of FIG. 3 facilitates the orientation. In contrast to the embodiment of the elastic element 300 depicted in FIG. 3, only two cut-outs have been introduced here along the x-axis, which form in a concave manner the peripheries of the elastic element 400 located in the z-direction.

FIG. 5 shows an engagement element 145 of the electric motor 115 from FIG. 1 in a further embodiment. A lug is stamped from the pole pot 205 of the electric motor 115 and bent towards the outside in order to form the engagement element 145. The lug 145 is thereby slotted in the form of a fork. Such an engagement element 145 is used in the prior art in order to engage in a dumbbell-shaped, vertically oriented elastic element 130.

FIG. 6 shows an elastic element 600 for engaging with the lug 145 from FIG. 5. A coordinate system displays again a radial direction x, an axial direction y and a circumferential direction z. Outer limitations of the elastic element 600 resemble the limitations of the elastic element 300 from FIG. 3. The recess 305 is, however, not cylindrical but slot-shaped in order to receive the lug 145 from FIG. 5. A transition between the slot-shaped recess 305 and the adjoining outer periphery of the elastic element 600 is rounded off on a side of said elastic element 600 that is radially remote from the electric motor. The rounded section can, like other rounded sections on said elastic element 130, contribute to a surface area of said elastic element 130 being enlarged and the risk of cracks in the region of sharp edges or corners being prevented.

FIG. 7 shows a further engagement element 145 on the electric motor 115 from FIG. 1. Similar to the embodiment of FIG. 5, a lug is stamped from the pole pot 205 of the electric motor 115 and bent towards the outside, wherein lateral sections of the lug are bent downwards in the axial direction in the embodiment depicted. A cross-section of the engagement element 145 therefore has substantially the form of a reversed U.

FIG. 8 shows an elastic element 800 for engaging with the engagement element 700 from FIG. 7. A coordinate system is also plotted here for improved orientation. The view of the elastic element 800 takes place from the interior of the housing 120. The recess 305 corresponds to the lug 145 from FIG. 7 and has in cross-section substantially the form of a reversed U.

FIG. 9 shows a flow diagram of a method 900 for producing a drive device 110 corresponding to FIG. 1. The engagement element 145 is thereby embodied in the form of a steel wire as described above in reference to FIG. 2. The elastic element 130 is correspondingly shaped, for example like the elastic element 300 from FIG. 3 or the elastic element 400 from FIG. 4.

In a first step 905, the steel wire 145 from FIG. 2 is inserted with the non-upset side forwards into the corresponding recess in the pole pot 205. In a subsequent step 910, the flux-return ring 210 is inserted into the pole pot 205 such that the upset side is in contact with said pole pot 205. In step 915, the flux-return ring is then connected to said pole pot, preferably by means of clinching, welding or adhesive bonding. The steel wire is subsequently mounted in the radial direction to the electric motor 115 in a form-fitting and force-fitting manner.

In a subsequent step 920, the elastic element 300, 400 is slid axially onto the steel wire 145. The electric motor 115 is then together with the elastic element 300, 400 inserted into the housing 120 such that said elastic element 300, 400 comes to rest in the recess 135 of the housing 120. Finally the cover 125 is mounted on the housing 120. An axial position of said elastic element 300, 400 is thereby fixed in a preferred manner. 

1. A drive device (110) for a fan module (100), said drive device (110) comprising the following: an electric motor (115); a housing (120); and a vibration damper (135, 300, 400, 600, 800) for fastening the electric motor (115) to the housing (120) in a manner which damps vibrations; wherein the electric motor (115) has a radial engagement element (145) for engaging into the vibration damper (135, 300, 400, 600, 800), and the housing (120) has a radial recess (135) for receiving the vibration damper (135, 300, 400, 600, 800), characterized in that the vibration damper (135, 300, 400, 600, 800) frames the engagement element (145) on a radial section.
 2. The drive device (110) according to claim 1, characterized in that the vibration damper (135, 300, 400, 600, 800) is formed such that a spring stiffness of said vibration damper (135, 300, 400, 600, 800) along the circumferential direction of the electric motor is less than parallel to the rotational axis of the electric motor (115).
 3. The drive device (110) according to claim 1, characterized in that the vibration damper (135, 300, 400, 600, 800) has a radial cut-out with regard to a shape of the recess (135) in order to reduce a contact surface to the recess (135) in the circumferential direction of the electric motor (115).
 4. The drive device (110) according to claim 1, characterized in that the vibration damper (135, 300, 400, 600, 800) is shaped such that a radial outer side of said vibration damper (135, 300, 400, 600, 800) is curved in order to rest against a section of the housing (120).
 5. The drive device (110) according to claim 1, characterized in that the vibration damper (135, 300, 400, 600, 800) is shaped such that a periphery located in the circumferential direction of the electric motor (115) rests in a planar fashion against a corresponding periphery of the recess (135).
 6. The drive device (110) according to claim 1, characterized in that the engagement element (145) comprises a round metal web which is fastened to a pole pot (205) of the electric motor (115).
 7. The drive device (110) according to claim 6, characterized in that the metal web (145) is upset on one end, wherein the upset end is disposed between the pole pot (205) and a flux-return ring (210) of the electric motor (115).
 8. The drive device (110) according to claim 1, characterized in that the vibration damper (135, 300, 400, 600, 800) is symmetrically shaped with respect to a rotation about a radius of the electric motor (115).
 9. The drive device (110) according to claim 1, characterized in that provision is made for a cover (125) which axially closes the housing (120), wherein the vibration damper (135, 300, 400, 600, 800) is held in the axial direction in a form-fitting manner between a limitation of the recess (135) and the cover (125).
 10. A method (900) for producing a drive device (110) according to claim 6 comprising the following steps: inserting (905) the metal web (145) through a corresponding cut-out in the pole pot (205); inserting (910) the flux-return ring (210) into the pole pot (205); connecting (915) the flux-return ring (210) to the pole pot (205); sliding (920) the vibration damper (135, 300, 400, 600, 800) onto the metal web (145); and inserting (925) the electric motor (115) into the housing so that the vibration damper (135, 300, 400, 600, 800) is received in the recess (135) of the housing (120). 